The signal came from Russia just weeks before their Zapad exercise, and was clearly intentional.

https://www.nrk.no/finnmark/stoy-fra-russland-slo-ut-gps-sig...

This time it was only blocking GPS signals. Previously this year Russia spoofed GPS signals over the black sea, sending false position data to ships in the area.

https://maritime-executive.com/editorials/mass-gps-spoofing-...